1. Field of the Invention
This invention relates to a power supply circuit system with a function to self-adjust current consumption.
2. Description of the Related Art
In a conventional power supply circuit system, a boosted voltage generated with a charge pump circuit is adjusted to a predetermined voltage with a voltage regulator circuit before being supplied to a load circuit. When the boosted voltage from the charge pump circuit reaches the predetermined voltage, an excess current from the charge pump circuit is consumed by flowing to a ground through the voltage regulator circuit in this case. Suppressing consumption of the current from the charge pump circuit substantially contributes for suppressing current consumption of an LSI as a whole, in which the power supply circuit system is incorporated.
There has been known a system which detects the boosted voltage, that is generated with the charge pump circuit and adjusted with the voltage regulator circuit, and adjusts an operating frequency or the like of the charge pump circuit when the boosted voltage reaches the predetermined voltage.
Technologies described above are disclosed in Japanese Patent Application Publication Nos. 2008-99370 and 2008-125267, for example.
However, the power supply circuit system, which detects the boosted voltage, that is generated with the charge pump circuit and adjusted with the voltage regulator circuit, and adjusts the operating frequency or the like of the charge pump circuit when the boosted voltage reaches the predetermined voltage, has a problem that there are large ripples in the output voltage (boosted voltage). In addition, the conventional power supply circuit system is not capable of keeping a stable output voltage when a loading amount to the load circuit varies abruptly.